On Tue, 28 Jun 2022 09:59:51 +0300
Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> This works, but technically it uses "num_in_bus_fmts" before it has been
> initialized so it leads to static checker warnings and probably KMEMsan
> warnings at run time. Reverse the checks so it checks for failure first
> and then check for unsupported formats next.
>
> Fixes: f32df58acc68 ("drm/bridge: Add the necessary bits to support bus format negotiation")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_bridge.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index e275b4ca344b..00cbde654472 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -897,10 +897,10 @@ static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
> conn_state,
> out_bus_fmt,
> &num_in_bus_fmts);
> - if (!num_in_bus_fmts)
> - return -ENOTSUPP;
> - else if (!in_bus_fmts)
> + if (!in_bus_fmts)
> return -ENOMEM;
> + else if (!num_in_bus_fmts)
> + return -ENOTSUPP;
Well, it changes the error we return when num_in_bus_fmts = 0
&& in_bus_fmts == NULL which is not an ENOMEM situation, so I'd rather
initialize num_{in,out}_bus_fmts to 0 here.
>
> if (first_bridge == cur_bridge) {
> cur_state->input_bus_cfg.format = in_bus_fmts[0];
> @@ -993,10 +993,10 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
> crtc_state,
> conn_state,
> &num_out_bus_fmts);
> - if (!num_out_bus_fmts)
> - return -ENOTSUPP;
> - else if (!out_bus_fmts)
> + if (!out_bus_fmts)
> return -ENOMEM;
> + else if (!num_out_bus_fmts)
> + return -ENOTSUPP;
> } else {
> num_out_bus_fmts = 1;
> out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
